In such timepieces the position of the axis of rotation of each pivoting element relative to that of the other pivoting elements must be maintained with a great accuracy. Therefore, in the known timepieces (for example in that disclosed in Swiss Pat. No.: 130727), the pivoting elements are pivoted in the plate which is made of metal. However, in order to decrease the cost price of the timepiece it is desirable to employ a plate made at least partly of plastics material.